Molding apparatus for molding material



Jan. 19, 1954 R. J. SHERMAN MOLDING APPARATUS FOR MoLDING MATERIAL 2 Sheets-Sheet 1 Filed/Nov. 9. 195o .Sia SIAE- EJE:Weg

NUMDOm.

Jan. 19, 1954 R, J, SHERMAN 2,666,230

MOLDING APPARATUS FOR MOLDING MATERIAL Filed Nov. 9, 1950 v 4 Z7 Zw??? Patented Jan. 19,v 1954 w Momma APPARATUS :FonfMonnme MATERIAL @W911i Sherman Great Necnn. x. Y 'Apuatinnxuemher 9 1950 Serial'No.

B Claimsl'Finis :invention relates jto prenorezeperated .inject-.ion molding rand/or dieoastipe Erpe invention l more nartioiilarly adapted to suoli melanie and/or pasting hines wherein the frnold .seotions `are nrrnly loesediri sa closed e Vnos;iti'on fonder ypotessi.1re lining tile injection Volucles separable mold lor lolie members paving i .lcavities formed to the sllape -oi the parts to loe rrpoliiecl.- in operation itl-.1e yirnolten .or plastioized material is 'in-looted tlie .dieor mold cavities through entrances during a period of time fvylglen the constituent members of 'the -moldpr die (are .held together pressione, referred tto aas the -inieotion :and `tpe croatia-1 :is permitted to pool'for set with presser-e removed., during .a `period tailed itlie cooling no1 solidit ie period, a-fter tlie irnold or. 1e members are @lisensased and the .npislleo product isremoved from tlie mold or rile..

.In current apparatus of the type vherein .reierree toI tlle-aioresaidprocedure results-in some distortion-oi the iorirledartiole 'luis-distortion of Y.shape and change of dimension or molded VKpart is .a oliaraeteristic -oi the machine and 4.is

"believed aus to 'tpe-sli nlraae'oi ftlle molten material-as .it oools toftli. -solidvstate- It a prime oloiect oi :ny :invention to provide improved molding ang/or agsting apparatus wn ein tpe sliriplsaee :or distortion oi the .formed e due to cooling oi tlie molten material area 4lv replaced.. Y

It is fortifier oloieot oi Ins invention to-proirioe-rpoldipe orcastinfsV apparatus utili-.zipsmultiple cavity molds dies vWliereip the appais Aadapted to simultaneously-mold or cast `sever-.al articles A'of dilerent shapes andzsizes in one circle of operation,

alt is a iurtlier -oloieot -oi-my invention topro- Vide an ,improved .nsiorreieoting trie molded or cast articles tr in the molds or dies. at the completicnoi the Qldiiiepyole .In general. my invention involves `tlle principle oi :applying -a --iiniicrin pressure to the cavity wherein the. article .islieine-nilded during. the period of. cooling troni tllefxnolten vto trie solid state and permits. trie use vot predetermined Jiniiividual pressures wliere several articles ofdirieracesionariol e liratiipel Figure 1 is aside Vview of molding apparatus inoluding. the invention.

Figure .2 .a .sectional view `oi? the loase Aand novable platenoi tlsieapparatus closed posiion..

:Figure 3 ,is a view of the apparatus of `lille-iure 2 in .open position,

YFigure 4 lis a top evierv tot @a .mold pase embodying the invention equipped to sers/.e multiple cavity mold.

Figure 5 is a yview partially in section of a valve-such as lA, .IB/@ng JG,

Figure 6 .is a view `pa.ntially in :section of a valve suon 2A, Zlfand 2Q..

Referring -to the .drawings in ldetail and Figure l in particular, a e inaorporating the invention includes a y.statiopanv platen l0, iniettlon nozzle l2, locating a le., yhopper I1, injection eylinder l5 and injection Piston i8. A stationaryfmold .lll is .secured-to the lixed platen I0, and a counterpart movable mold .22 is secured to :a mold vlease .23 which in turn is .secured to a movable :platen f2.4 adapted to be moved by means oi :a toggle `ineohariism 28, motivated bra piston 25 Withinccylirider 21.

The pressure medium required to operate the .apparatus is -obtainediroma sonnce and transas fwill loe hereinafter rlesorlloed.

In one aspeet, :invention provides means for applying a v,desired pressureon the molded .parts Lduring the eooling and .solidiiyipg period of the .molding cycle. continued application oi Ypressure upon .the molded parts .during the cooling andI-solidiiiiingperiod forces the parts vto conform to tine size .and shape of the mold cavities.

VReferring Vto Figures 2 land .3, my invention includes a new and improved mold assembly. Movealole mold '22 is y,attapheii vto a. cooperating .pressure plus plate C44 adapted to simultaneously serve a pluralityotmoldstationsll. 'Pressure chamber .bleek 532 'isorined wltna `chamber 36,

kequipped with a-suitalo'le expandable diaphragm 38, which is retained .irl postionlby means of -moillltinglrings 40 and 4l.

Eaoh mold station '.34 isprovided with. a pres- .sure plug i4? mounted inipressureplug plate 44.

Eachpressiireplug 52 is adapted to apply presy sure to a die member 4.3 at each mold station si.. Pressure. .plug plate 44 is alsciailapted to receive the molo temperature control element 4e.

n ,further aspect oi 'nii' invention Aprovides means ifor ejecting'the Producti-from the 'molds chamber A plurality of pressure operated line opening valves IA, IB and IC, such as shown in Figure 5, are interconnected by means of lines J, K, L, E, M, F, G, H, and D, with a series of pressure operated line opening check valves 2A, 2B, and 2C, such as shown in"Figure 6, and adjustable relief valves 3A, 3B and 3C (not shown) and operated to control the pressures applied to the mold as hereinafter described.

To accomplish my object of retaining the material under pressure during the cooling and hardening period I will first describe a phase of operation which I call injection-compression cycle. The injection compression cycle as referred to herein includes the injection of the molten materials to the dies or molds and the cooling and solidifying of the material to form a product. l

Referring to the drawings, upon opening presi sure line A, a pressure is applied to the injection cylinder I6, injection piston i8 is moved forward under the line pressure forcing a charge of raw material from hopper Il into the heater I4 and ejecting the formerly heated material through a nozzle I2, sprue bushing, runners and gates into the mold cavities formed by `mold members and 22.

When the molds are lled, or nearly lled, the pressure in line A rises and is transmitted through line J to line valve IA closing said valve. With valve IA closed the pressure in line J continues to increase and causes line opening valve 2A to open and pass the pressure medium through line K and valve 3A to lines L and M. As lines L and M are filled With the pressure medium, the pressure reaches a level sufficiently high to cause valve IBI to close.

The time required for valve IB to close is determined by the rate of ilow through valve 3A, and permits valve IB to act as a delay valve, insuring the lling of the molds before pressure is built up in the pressure chamber 36.

Closure of valve IB results in a back pressure in lines L and M, causing line opening valve 2B to open and permit the medium under pressure to flow into line E. At this point, with valve IB closed and valve IC open, the medium under pressure flows through valve IC and line F to 4the pressure chamber block 32, pressure chamber 36 and cause the associated expandable diaphragm 36 to expand. Relief valve 3B in line E is used as a control for the pressure in the line and serves as a Icy-pass to drain line D.

The presence of a medium order pressure in pressure chamber 36 acting against'expandable diaphragm 38 causes pressure plug 42 to place Ymoveable die or mold members 43' in pressured contact with stationary mold member 20. The amount of pressure exerted on each mold mem- .ber is determined by the cross-sectional Yarea of the head of pressure plug 42, and permits use of a multiple cavity mold wherein each mold may' beA retained in position under a different pre-determinedpressure. y .l iisnieralbflireile f ,lm .line A, @ed rette?" `ing the ejection of the product.

means of toggle lever mechanism 28. When the piston 26 Vreaches the end of its stroke the pressure in line B rises and is transmitted through valve 3D and line H to valve iC and closes valve IC. Closure of valve IC causes the pressure in line Htc open the line opening check valve 2C permitting the medium under pressure to pass from line H to line G, F and the pressure charnber 36, diaphragm 38 and pressure plug 42, caus- Removal of pressure from line B causes valve 2C to close and valve IC to open by exhaustion through lines H and B permitting the pressure chamber 36 to exhaust through lines F and E and valve IB to line'D setting the system back to its initial state.

While lf. have herein shown and described certain preferred embodiments of my invention, I wish it to be understood that I do not confine myself to all of the precise detail herein set forth, as modification and variations may be Vmade Without departing from the spirit of the invention or exceeding the scope of the appended claims.

What is claimed is:

1. Injection molding apparatus including a mold comprising fixed die members and moveable die members forming a plural cavity mold when placed in engagement, means for injecting a moldable material into said mold, a pressure plug plate having a plurality of pressure plugs, a pressure plug in engagement with each of said moveable die members, a pressure chamber block, an expandable diaphragm between said pressure chamber block and said pressure plug plate and adapted to impart pressure to -said pressure plugsl and means for introducing a medium having a`predetermined pressure to said pressure chamber block during the cooling and solidifying of a. moldable material injected into said mold cavities.

injection molding apparatus including a plural 'cavity' mold comprising a fixed die member and a moveable die member forming a mold 'cavity when placed Vin engagement,Y means for injecting a moldable material into said cavities, `means for maintaining said moldable material in each of said cavities under individual predetermined pressures during cooling -andvsolidifying Within said mold cavities, said means being `adapted to Veject said molded material after vwhen placed in engagement, means for injecting a moldable material into said mold, a pressure plug plate having a plurality of pressure plugs, a pressure plug in engagement with each of said moveable die members, a pressure c hamber block, an expandable diaphragm between said pressure chamber block and said pressure plug plate and adapted to impart pressure to said pressure plugs, means for introducing a mediuml a predetermined pressure to of said moldable material.

ber comprising a plurality of molds, each of said molds including a moveable die member, a pressure plug plate adjacent the rear of said moveable mold member, one end of a pressure plug secured to said moveable die members and extending through said pressure plug plate, a pressure chamber block including an expandable diaphragm adjacent said pressure plug plate and having said diaphragm in contact with each of the respective extremities of said pressure plugs, means for injecting a moldable material into said mold, and means for introducing a pressure medium into said pressure chamber after said material has been injected into said mold.

5. Injection molding apparatus including a xed platen and a moveable platen, a split cavity mold comprising a fixed mold member and a moveable mold member having a plurality of molds and secured to said fixed and moveable platens respectively, said moveable mold member comprising a plurality of molds, each of said molds including a moveable die member, a pressure plug plate adjacent the rear of said moveable mold member, one end of a pressure plug secured to said moveable die member and extending through said pressure plug plate, a pressure chamber block including an expandable diaphragm adjacent said pressure plug plate and 6 having said diaphragm in contact with each of the respective extremities of said pressure plugs, a pressure medium source, a closed cylinder including a pressure actuated ram extending from said cylinder and adapted to be actuated by said pressure medium source to inject a moldable material into said mold, and delay means operative by said pressure medium source to apply a pressure medium to said pressure chamber block after said moldable material has been injected into said mold.

6. Injection molding apparatus including a mold comprising iixed die members and moveable die members forming a plural cavity mold when placed in engagement, means for injecting a moldable material into said mold, a pressure plug plate having a plurality of pressure plugs, a pressure plug in engagement with each of said moveable die members, means for imparting predetermined individual pressures to each of said pressure plugs after filling and during cooling and solidifying of the moldable material within said mold cavity, and means for ejecting said moldable material after solidication thereof.

RUSSELL J. SHERMAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,233,057. Luce Feb. 25, 1941 2,423,914 Wacker July 15, 1947 2,443,826 Johnson June 22, 1948 2,470,402 Jobst May 17, 1949 OTHER REFERENCES Modern Plastics, September 1945, pp. 146-150. 

